| Parameter | Description | Suggested value/range |
|---|---|---|
| memory_chunk_cache_size | The total cache size of the memory allocator. | The default value is 0. We recommend that you use the default value. |
| minor_warm_up_duration_time | The MemTable warm-up period. | The warm-up period starts when the minor compaction is completed and ends when all traffic in the corresponding partitions is switched from the MemTable to the SSTable. We recommend that you set it to 0. In this case, the traffic is immediately switched to the SSTable and the MemTable is immediately released after the minor compaction. |
| _enable_parallel_minor_merge | Specifies to enable parallel minor compactions within a partition. | We recommend that you enable this feature to improve the minor compaction efficiency for large partitions. |
| minor_merge_concurrency | The number of minor compaction threads. | We recommend that you set a large value for this parameter to accelerate minor compactions. |
| memory_limit_percentage | The maximum percentage of total memory that OceanBase Database can use. | We recommend that you set this parameter to a large value. |
| memstore_limit_percentage | The maximum percentage of MemStore memory in the tenant memory, which is non-exclusive. | Set this parameter to an appropriate large value. An excessively large MemStore memory may cause the data writing speed to overrun the minor compaction speed and increase the risk of memory overflow. |
| freeze_trigger_percentage | The threshold for triggering a minor compaction. | For systems with heavy write load, we recommend that you set the value to 30 to 50. This setting can trigger a minor compaction as soon as possible to avoid out-of-memory errors. However, minor compactions bring about additional CPU and I/O overhead. Frequent minor compactions generate an increasing number of mini SSTables, which increases the query path and degrades the query performance. |
| minor_freeze_times | The number of minor compactions to trigger a major compaction. | We recommend that you set this parameter to a large value to avoid major compactions during tests. |
| _mini_merge_concurrency | The number of mini merge threads. | We recommend that you set this parameter to a large value to accelerate mini merge. |
| _flush_clog_aggregation_buffer_timeout | The timeout period for refreshing the clog aggregation buffer. | We recommend that you set the value to 2 ms. |
| _clog_aggregation_buffer_amount | The size of the clog aggregation buffer. | We recommend that you set the value to 4. |
| system_memory | The memory size reserved by the system for the tenant with the ID 500. |
We recommend that you use the default value. |
| use_large_pages | Specifies whether to enable large memory pages. | The large memory pages feature takes effect only when it is enabled on the OS side. We recommend that you enable this feature to improve the query efficiency of memory page tables. |
Memory-related parameters
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